Could it be the end of "Friends"? In its latest cover story, PEOPLE stews over the possibility that the top-rated NBC sitcom could be heading into the sunset. "It's heartbreaking," Jennifer Aniston, 32, said last week. "If I think about it, it chokes me up to realize this will be over. It's been a pretty intense eight years for this group of people. Major crossroads in our lives we were at together, so it's very, very sad." (NBC, meanwhile, is still hoping that the actors will sign on for a ninth season. "We would like the show to continue for as long as the cast wants to do it," says NBC Entertainment President Jeff Zucker.) To their credit, as their salaries reportedly have inflated to $750,000 per episode, the female "Friends" stars, Aniston, Courteney Cox Arquette, 37, and Lisa Kudrow, 38 (and male stars Matthew Perry, 32, David Schwimmer, 34, and Matt LeBlanc, 34, as well) have kept their egos in check and their loyalties in line. "No one seems jealous of any of the others," says a source on the set. "The girls are all still friends." They just have less time for each other offscreen, given their respective film and family obligations. "People do grow up," says David Crane, the show's co-creator. "Their lives and priorities shift."